DOCSLIB.ORG

Preservation Management of Digital Materials: the Handbook

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Preservation Management of Digital Materials: the Handbook Preservation Management of Digital Materials: The Handbook www.dpconline.org/graphics/handbook/ 5. Media and Formats 5. Outline Intended primary audience Operational managers and staff in repositories, publishers and other data creators, third party service providers. Assumed level of knowledge of digital preservation Novice to Intermediate. Purpose To outline the range of options available when creating digital materials and some of the major implications of selection.To point to more detailed sources of advice and guidance.To indicate areas where it is necessary to maintain an active technology watch. 5.1 Media It is important to have an understanding of the various media for storage because they require different software and hardware equipment for access, and have different storage conditions and preservation requirements.They also have varying suitability according to the storage capacity required, and preservation or access needed. Although it is very easy to focus on the traditional conservation of the physical artefact, it is important to recognise that most electronic media will be threatened by obsolescence of the hardware and software to access them.This often occurs long before deterioration of media (which have been subject to appropriate storage and handling) becomes a problem. However, appropriate selection, storage and handling of media is still essential to any preservation strategy (see Storage and Preservation). Obsolescence of previous storage media has occurred in rapid succession. In floppy disks alone we have seen a progression from 8 in to 5.25 in and then 3.5 in formats, with each change leading to rapid discontinuation of previous formats and difficulty in obtaining or maintaining access devices for them. Mass storage devices have a long history and this section deals only with the magnetic and optical storage media which are in widespread or recent use. An interesting historical account of "new media" can be found in the PRO Preservation Guide series (Farley 1999). Magnetic media Consist of a variety of magnetic media and containers including a range of magnetic tapes (e.g. reels, cartridges and cassettes) and disks (e.g. hard disks, floppy disks).They all utilise the magnetic properties of metallic materials suspended in a non-magnetic mixture on a substrate or backing material. 152 The Handbook was first compiled by Neil Beagrie and Maggie Jones and is now maintained and updated by the DPC. Digital Preservation Coalition November 2008 Website: www.dpconline.org Email: [email protected] Preservation Management of Digital Materials: The Handbook www.dpconline.org/graphics/handbook/ This provides a versatile and cheap storage medium and both the storage capacity and the ability to retain the magnetic charges holding the data have increased substantially in recent years.The method of construction and storing the data also point to potential weaknesses of magnetic media. You should ensure appropriate storage away from strong magnetic fields as these may alter the media and lead to data loss (e.g. electrical equipment and motors). Damage from magnetic fields is rare and the media normally has to be in very close proximity (<50 mm) for this to occur. Tape enclosures or packing with a space clearance of 50 mm around the media is recommended for use during transportation and transfer. Clean operating conditions and environments will reduce the scope for damage to media and devices.The high density of storage and the close proximity of device heads to the media mean even small particles such as smoke or other debris can lead to data loss. Handling and use of magnetic storage media should be minimised to reduce wear, or refreshment cycles implemented (as recommended by the manufacturer) to replace media on a more frequent basis reflecting the levels of use. Poor environmental storage may also lead to oxidation of the ferromagnetic material or problems with the "binding" layer or substrate materials. Recommendations for the storage environment of magnetic media are provided in Storage and Preservation. Magnetic media are constantly evolving and in addition to fundamental changes in devices manufacturers often undertake an almost constant evolution of production processes. Although the reliability of magnetic media has improved over recent years it is important to be aware that faults in manufacture can occur and to make appropriate checks of new media when purchased. Media should also be of high quality and purchased from reputable brands and suppliers. As an additional safeguard archive copies can be made to comparable magnetic media purchased from different suppliers to guard against faults introduced into products or batches of the product by the manufacturers. In addition to the magnetic media themselves it is important that attention is paid to the recording and access devices such as tape drives.These should be of good quality and well- maintained. Problems with the access devices e.g. head/media crashes are one of the most common cases of damage to magnetic storage media. It may also be desirable to write archive copies from different devices and software to protect data form malfunctioning devices or software. Optical media Optical storage media such as CD-ROM (Compact Disc - Read Only Memory), CD-R (Compact Disc -Recordable), and DVD-ROM (Digital Versatile Disc - Read Only Memory) use laser light to read from a data layer. In CD-ROM this data layer consists of a series of pits and plateaux in a metallic coating over a plastic disk. A clear acrylic coating is applied to the metallic layer to protect it from scratches and corrosion. CD-R employs a dye layer which is light sensitive as the data layer. Data is written to and read back using laser light.The use of 153 The Handbook was first compiled by Neil Beagrie and Maggie Jones and is now maintained and updated by the DPC. Digital Preservation Coalition November 2008 Website: www.dpconline.org Email: [email protected] Preservation Management of Digital Materials: The Handbook www.dpconline.org/graphics/handbook/ light sensitive dyes means CD-Rs are less stable than CD-ROMs and more concerns have been raised over their use as archival media (Ross and Gow 1999). As with magnetic media there is considerable diversity in practice and production of CD-R and greater care is needed in selecting high quality media from reputable suppliers for archival purposes. DVD-ROM is a more recent optical storage medium with capacity to store 4.7-18 Gb. Optical disks are an increasingly popular method of storage.The device reader is not in contact with the disk and mechanical failure is less likely to lead to data loss than damage to the disk itself through poor handling or storage. Disks should not be flexed or their surfaces marked or abraded e.g. through use of a sharp pen or pencil for labelling.The manufacturer's recommendation for marking should be followed. As with magnetic media, optical media have been subject to a constant process of evolution and changes in manufacture. The quality of the media, a reputable source, and appropriate handling and storage environment (see Storage and Preservation) will all affect its longevity. Media life Media should be refreshed on a regular cycle within the lifetime for archival storage identified by the manufacturer or independent sources such as the US National Media Laboratory. Sample generic figures for lifetimes of media under various temperature and humidity levels assuming optimal use (no or very infrequent access) and environmental conditions (stable and free of contaminants, u-v light and strong magnetic fields) are given in the figure below. It should be noted that the life of specific media will be dependent on the quality of manufacture. Media life will vary between specific products and dates (e.g. the earliest CDs will be more experimental in manufacture than current versions; branded "Gold" CDs will have longer life than cheaper standard products). Figure 7 Sample Generic Figures for Lifetimes of Media Device 25RH 30RH 40RH 50RH 50RH 10°C 15°C 20°C 25°C 28°C D3 magnetic 50 years 25 years 15 years 3 years 1 year tape DLT 75 years 40 years 15 years 3 years 1 year magnetic tapecartridge CD/DVD 75 years 40 years 20 years 10 years 2 years CD-ROM 30 years 15 years 3 years 9 months 3 months 154 The Handbook was first compiled by Neil Beagrie and Maggie Jones and is now maintained and updated by the DPC. Digital Preservation Coalition November 2008 Website: www.dpconline.org Email: [email protected] Preservation Management of Digital Materials: The Handbook www.dpconline.org/graphics/handbook/ After Dollar, NML and PRO 5.2 File Format and Standards As with storage media there is a diverse range of formats (e.g.Word,TIFF) in common use.The purpose of this section is not to provide a detailed or exhaustive list of current formats for different media types but to draw attention to the broader implications of file formats for their application, and implications for preservation.There are a number of excellent sources of more detailed advice on file formats and these are detailed in the further reading to the chapter. File formats are subject to similar rapid obsolescence and evolution and the process of selection and assessment of options for preservation is largely one of risk reduction. Use of file formats which have been well documented, have undergone thorough testing and are non- proprietary and usable on different hardware and software platforms minimises the frequency of migration and reduces the risk and costs in their preservation. Similarly utilising formats which have been widely adopted minimises risk as it is more likely that migration paths will be provided by the manufacturers and a degree of "backward compatibility" will be available between versions of the file format as it evolves.
Load more

Recommended publications
  • Hard Disk Drives
    37 Hard Disk Drives The last chapter introduced the general concept of an I/O device and showed you how the OS might interact with such a beast. In this chapter, we dive into more detail about one device in particular: the hard disk drive. These drives have been the main form of persistent data storage in computer systems for decades and much of the development of file sys- tem technology (coming soon) is predicated on their behavior. Thus, it is worth understanding the details of a disk’s operation before building the file system software that manages it. Many of these details are avail- able in excellent papers by Ruemmler and Wilkes [RW92] and Anderson, Dykes, and Riedel [ADR03]. CRUX: HOW TO STORE AND ACCESS DATA ON DISK How do modern hard-disk drives store data? What is the interface? How is the data actually laid out and accessed? How does disk schedul- ing improve performance? 37.1 The Interface Let’s start by understanding the interface to a modern disk drive. The basic interface for all modern drives is straightforward. The drive consists of a large number of sectors (512-byte blocks), each of which can be read or written. The sectors are numbered from 0 to n − 1 on a disk with n sectors. Thus, we can view the disk as an array of sectors; 0 to n − 1 is thus the address space of the drive. Multi-sector operations are possible; indeed, many file systems will read or write 4KB at a time (or more). However, when updating the disk, the only guarantee drive manufacturers make is that a single 512-byte write is atomic (i.e., it will either complete in its entirety or it won’t com- plete at all); thus, if an untimely power loss occurs, only a portion of a larger write may complete (sometimes called a torn write).
    [Show full text]
  • International Preservation Issues Number Seven International Preservation Issues Number Seven
    PROCEEDINGS OF THE INTERNATIONAL SYMPOSIUM THE 3-D’SOFPRESERVATION DISATERS, DISPLAYS, DIGITIZATION ACTES DU SYMPOSIUM INTERNATIONAL LA CONSERVATION EN TROIS DIMENSIONS CATASTROPHES, EXPOSITIONS, NUMÉRISATION Organisé par la Bibliothèque nationale de France avec la collaboration de l’IFLA Paris, 8-10 mars 2006 Ed. revised and updated by / Ed. revue et corrigée par Corine Koch, IFLA-PAC International Preservation Issues Number Seven International Preservation Issues Number Seven International Preservation Issues (IPI) is an IFLA-PAC (Preservation and Conservation) series that intends to complement PAC’s newsletter, International Preservation News (IPN) with reports on major preservation issues. IFLA-PAC Bibliothèque nationale de France Quai François-Mauriac 75706 Paris cedex 13 France Tél : + 33 (0) 1 53 79 59 70 Fax : + 33 (0) 1 53 79 59 80 e-mail: [email protected] IFLA-PAC Director e-mail: [email protected] Programme Officer ISBN-10 2-912 743-05-2 ISBN-13 978-2-912 743-05-3 ISSN 1562-305X Published 2006 by the International Federation of Library Associations and Institutions (IFLA) Core Activity on Preservation and Conservation (PAC). ∞ This publication is printed on permanent paper which meets the requirements of ISO standard: ISO 9706:1994 – Information and Documentation – Paper for Documents – Requirements for Permanence. © Copyright 2006 by IFLA-PAC. No part of this publication may be reproduced or transcribed in any form without permission of the publishers. Request for reproduction for non-commercial purposes, including
    [Show full text]
  • Analog, the Sequel: an Analysis of Current Film Archiving Practice and Hesitance to Embrace Digital Preservation by Suzanna Conrad
    ANALOG, THE SEQUEL: AN ANALYSIS OF CURRENT FILM ARCHIVING PRACTICE AND HESITANCE TO EMBRACE DIGITAL PRESERVATION BY SUZANNA CONRAD ABSTRACT: Film archives preserve materials of significant cultural heritage. While current practice helps ensure 35mm film will last for at least one hundred years, digi- tal technology is creating new challenges for the traditional means of preservation. Digitally produced films can be preserved via film stock; however, digital ancillary materials and assets in many cases cannot be preserved using traditional analog means. Strategy and action for preserving this content needs to be addressed before further content is lost. To understand the current perspective of the film archives, especially in regards to the film industry’s marked hesitation to embrace digital preservation, the Academy of Motion Picture Arts and Sciences’ paper “The Digital Dilemma: Strategic Issues in Archiving and Accessing Digital Motion Picture Materials” was closely evaluated. To supplement this analysis, an interview was conducted with the collections curator at the Academy Film Archive, who explained the archives’ current approach to curation and its hesitation to move to digital technologies for preservation. Introduction Moving images are a vital part of our cultural heritage. The music, film, and broadcasting industries, as well as academic and cultural institutions, have amassed a “legacy of primary source materials” of immense value. These sources make the last one hundred years understandable as an era of the “media of the modernity.”1 Motion pictures and films were established as vital archival records as early as the 1930s with the National Archives Act, which included motion pictures in the definition of “objects of archival interest.”2 As cultural artifacts, moving images deserve archival care and preservation.3 However, the art of preserving moving images and film can at times be daunting.
    [Show full text]
  • Nasdeluxe Z-Series
    NASdeluxe Z-Series Benefit from scalable ZFS data storage By partnering with Starline and with Starline Computer’s NASdeluxe Open-E, you receive highly efficient Z-series and Open-E JovianDSS. This and reliable storage solutions that software-defined storage solution is offer: Enhanced Storage Performance well-suited for a wide range of applica- tions. It caters perfectly to the needs • Great adaptability Tiered RAM and SSD cache of enterprises that are looking to de- • Tiered and all-flash storage Data integrity check ploy a flexible storage configuration systems which can be expanded to a high avail- Data compression and in-line • High IOPS through RAM and SSD ability cluster. Starline and Open-E can data deduplication caching look back on a strategic partnership of Thin provisioning and unlimited • Superb expandability with more than 10 years. As the first part- number of snapshots and clones ner with a Gold partnership level, Star- Starline’s high-density JBODs – line has always been working hand in without downtime Simplified management hand with Open-E to develop and de- Flexible scalability liver innovative data storage solutions. Starline’s NASdeluxe Z-Series offers In fact, Starline supports worldwide not only great features, but also great Hardware independence enterprises in managing and pro- flexibility – thanks to its modular archi- tecting their storage, with over 2,800 tecture. Open-E installations to date. www.starline.de Z-Series But even with a standard configuration with nearline HDDs IOPS and SSDs for caching, you will be able to achieve high IOPS 250 000 at a reasonable cost.
    [Show full text]
  • Use External Storage Devices Like Pen Drives, Cds, and Dvds
    External Intel® Learn Easy Steps Activity Card Storage Devices Using external storage devices like Pen Drives, CDs, and DVDs loading Videos Since the advent of computers, there has been a need to transfer data between devices and/or store them permanently. You may want to look at a file that you have created or an image that you have taken today one year later. For this it has to be stored somewhere securely. Similarly, you may want to give a document you have created or a digital picture you have taken to someone you know. There are many ways of doing this – online and offline. While online data transfer or storage requires the use of Internet, offline storage can be managed with minimum resources. The only requirement in this case would be a storage device. Earlier data storage devices used to mainly be Floppy drives which had a small storage space. However, with the development of computer technology, we today have pen drives, CD/DVD devices and other removable media to store and transfer data. With these, you store/save/copy files and folders containing data, pictures, videos, audio, etc. from your computer and even transfer them to another computer. They are called secondary storage devices. To access the data stored in these devices, you have to attach them to a computer and access the stored data. Some of the examples of external storage devices are- Pen drives, CDs, and DVDs. Introduction to Pen Drive/CD/DVD A pen drive is a small self-powered drive that connects to a computer directly through a USB port.
    [Show full text]
  • Nanotechnology Trends in Nonvolatile Memory Devices
    IBM Research Nanotechnology Trends in Nonvolatile Memory Devices Gian-Luca Bona [email protected] IBM Research, Almaden Research Center © 2008 IBM Corporation IBM Research The Elusive Universal Memory © 2008 IBM Corporation IBM Research Incumbent Semiconductor Memories SRAM Cost NOR FLASH DRAM NAND FLASH Attributes for universal memories: –Highest performance –Lowest active and standby power –Unlimited Read/Write endurance –Non-Volatility –Compatible to existing technologies –Continuously scalable –Lowest cost per bit Performance © 2008 IBM Corporation IBM Research Incumbent Semiconductor Memories SRAM Cost NOR FLASH DRAM NAND FLASH m+1 SLm SLm-1 WLn-1 WLn WLn+1 A new class of universal storage device : – a fast solid-state, nonvolatile RAM – enables compact, robust storage systems with solid state reliability and significantly improved cost- performance Performance © 2008 IBM Corporation IBM Research Non-volatile, universal semiconductor memory SL m+1 SL m SL m-1 WL n-1 WL n WL n+1 Everyone is looking for a dense (cheap) crosspoint memory. It is relatively easy to identify materials that show bistable hysteretic behavior (easily distinguishable, stable on/off states). IBM © 2006 IBM Corporation IBM Research The Memory Landscape © 2008 IBM Corporation IBM Research IBM Research Histogram of Memory Papers Papers presented at Symposium on VLSI Technology and IEDM; Ref.: G. Burr et al., IBM Journal of R&D, Vol.52, No.4/5, July 2008 © 2008 IBM Corporation IBM Research IBM Research Emerging Memory Technologies Memory technology remains an
    [Show full text]
  • Instructions and Dehinitions: FY2014
    Instructions and Deinitions: FY2014 Table of Contents Introduction 2 Background 2 What’s New for the FY2014 Survey 2 FAQ 4 General Instructions 6 General Information 6 Section 1: Conservation Treatment 8 Section 2: Conservation Assessment, Digitization Preparation, Exhibit Preparation 9 Section 3: General Preservation Activities 10 Section 4: Reformatting and Digitization 10 Section 5: Digital Preservation and Digital Asset Management 13 Introduction Count what you do and show preservation counts! The Preservation Statistics Survey is an effort coordinated by the Preservation and Reformatting Section (PARS) of the American Library Association (ALA) and the Association of Library Collections and Technical Services (ALCTS). Any library or archives in the United States conducting preservation activities may complete this survey, which will be open from January 20, 2015 through February 27, 2015. The deadline has been extended to March 20, 2015. Questions focus on production-based preservation activities for /iscal year 2014, documenting your institution's conservation treatment, general preservation activities, preservation reformatting and digitization, and digital preservation and digital asset management activities. The goal of this survey is to document the state of preservation activities in this digital era via quantitative data that facilitates peer comparison and tracking changes in the preservation and conservation /ields over time. Background This survey is based on the Preservation Statistics survey program by the Association of Research Libraries (ARL) from 1984 to 2008. When the ARL Preservation Statistics program was discontinued in 2008, the Preservation and Reformatting Section of ALA / ALCTS, realizing the value of sharing preservation statistics, worked towards developing an improved and sustainable preservation statistics survey.
    [Show full text]
  • Archiving Online Data to Optical Disk
    ARCHIVING ONLINE DATA TO OPTICAL DISK By J. L. Porter, J. L. Kiesler, and D. A. Stedfast U.S. GEOLOGICAL SURVEY Open-File Report 90-575 Reston, Virginia 1990 U.S. DEPARTMENT OF THE INTERIOR MANUEL LUJAN, JR., Secretary U.S. GEOLOGICAL SURVEY Dallas L. Peck, Director For additional information Copies of this report can be write to: purchased from: Chief, Distributed Information System U.S. Geological Survey U.S. Geological Survey Books and Open-File Reports Section Mail Stop 445 Federal Center, Bldg. 810 12201 Sunrise Valley Drive Box 25425 Reston, Virginia 22092 Denver, Colorado 80225 CONTENTS Page Abstract ............................................................. 1 Introduction ......................................................... 2 Types of optical storage ............................................... 2 Storage media costs and alternative media used for data archival. ......... 3 Comparisons of storage media ......................................... 3 Magnetic compared to optical media ............................... 3 Compact disk read-only memory compared to write-once/read many media ................................... 6 Erasable compared to write-once/read many media ................. 7 Paper and microfiche compared to optical media .................... 8 Advantages of write-once/read-many optical storage ..................... 8 Archival procedure and results ........................................ 9 Summary ........................................................... 13 References ..........................................................
    [Show full text]
  • Can We Store the Whole World's Data in DNA Storage?
    Can We Store the Whole World’s Data in DNA Storage? Bingzhe Li†, Nae Young Song†, Li Ou‡, and David H.C. Du† †Department of Computer Science and Engineering, University of Minnesota, Twin Cities ‡Department of Pediatrics, University of Minnesota, Twin Cities {lixx1743, song0455, ouxxx045, du}@umn.edu, Abstract DNA storage can achieve a theoretical density of 455 EB/g [9] and has a long-lasting property of several centuries [10,11]. The total amount of data in the world has been increasing These characteristics of DNA storage make it a great candi- rapidly. However, the increase of data storage capacity is date for archival storage. Many research studies focused on much slower than that of data generation. How to store and several research directions including encoding/decoding asso- archive such a huge amount of data becomes critical and ciated with error correction schemes [11–18], DNA storage challenging. Synthetic Deoxyribonucleic Acid (DNA) storage systems with microfluidic platforms [19–21], and applications is one of the promising candidates with high density and long- such as database on top of DNA storage [9]. Moreover, sev- term preservation for archival storage systems. The existing eral survey papers [22,23] on DNA storage mainly focused works have focused on the achievable feasibility of a small on the technology reviews of how to store data in DNA (in amount of data when using DNA as storage. In this paper, vivo or in vitro) including the encoding/decoding and synthe- we investigate the scalability and potentials of DNA storage sis/sequencing processes. In fact, the major focus of these when a huge amount of data, like all available data from the studies was to demonstrate the feasibility of DNA storage world, is to be stored.
    [Show full text]
  • Content Preservation and Digitization of Maps Housed in the KU Natural History Museum Division of Archaeology: an Analysis of Op
    1 Content Preservation and Digitization of Maps Housed in the KU Natural History Museum Division of Archaeology: An Analysis of Opportunities and Obstacles By Ross Kerr A study presented in partial fulfillment of the requirements for the degree of Master of Arts in Museum Studies The University of Kansas April 27 2017 *Address for correspondence: [email protected] *With special thanks to Dr. Sandra Olsen, Dr. Peter Welsh, and Mr. Steve Nowak for serving on my committee and overseeing my research. 2 Abstract The purpose of this research is to explain the obstacles museums face in preserving map collections, as well as the steps museums can take to overcome these obstacles. The research begins with a brief history of paper conservation of maps in museums and libraries, and digitization of maps. Next, there is an explanation of the theoretical framework/approach that is used in this project. Following that is a presentation of a SWOT analysis of the archaeological map collection held by the KU Biodiversity Institute & Natural History Museum. The first two components of the SWOT analysis, strengths and weaknesses, focus on advantages and shortcomings of the collection in its current state. The last two components, opportunities and threats, focus respectively on the benefits that can be expected from preserving the map collection, and the obstacles that may hinder process. Finally, the study outlines a procedure for preserving and digitizing the archaeological maps held by the KU Biodiversity Institute, in order to expand accessibility
    [Show full text]
  • The Future of DNA Data Storage the Future of DNA Data Storage
    The Future of DNA Data Storage The Future of DNA Data Storage September 2018 A POTOMAC INSTITUTE FOR POLICY STUDIES REPORT AC INST M IT O U T B T The Future O E P F O G S R IE of DNA P D O U Data LICY ST Storage September 2018 NOTICE: This report is a product of the Potomac Institute for Policy Studies. The conclusions of this report are our own, and do not necessarily represent the views of our sponsors or participants. Many thanks to the Potomac Institute staff and experts who reviewed and provided comments on this report. © 2018 Potomac Institute for Policy Studies Cover image: Alex Taliesen POTOMAC INSTITUTE FOR POLICY STUDIES 901 North Stuart St., Suite 1200 | Arlington, VA 22203 | 703-525-0770 | www.potomacinstitute.org CONTENTS EXECUTIVE SUMMARY 4 Findings 5 BACKGROUND 7 Data Storage Crisis 7 DNA as a Data Storage Medium 9 Advantages 10 History 11 CURRENT STATE OF DNA DATA STORAGE 13 Technology of DNA Data Storage 13 Writing Data to DNA 13 Reading Data from DNA 18 Key Players in DNA Data Storage 20 Academia 20 Research Consortium 21 Industry 21 Start-ups 21 Government 22 FORECAST OF DNA DATA STORAGE 23 DNA Synthesis Cost Forecast 23 Forecast for DNA Data Storage Tech Advancement 28 Increasing Data Storage Density in DNA 29 Advanced Coding Schemes 29 DNA Sequencing Methods 30 DNA Data Retrieval 31 CONCLUSIONS 32 ENDNOTES 33 Executive Summary The demand for digital data storage is currently has been developed to support applications in outpacing the world’s storage capabilities, and the life sciences industry and not for data storage the gap is widening as the amount of digital purposes.
    [Show full text]
  • Computer Files & Data Storage
    STORAGE & FILE CONCEPTS, UTILITIES (Pages 6, 150-158 - Discovering Computers & Microsoft Office 2010) I. Computer files – data, information or instructions residing on secondary storage are stored in the form of a file. A. Software files are also called program files. Program files (instructions) are created by a computer programmer and generally cannot be modified by a user. It’s important that we not move or delete program files because your computer requires them to perform operations. Program files are also referred to as “executables”. 1. You can identify a program file by its extension:“.EXE”, “.COM”, “.BAT”, “.DLL”, “.SYS”, or “.INI” (there are others) or a distinct program icon. B. Data files - when you select a “save” option while using an application program, you are in essence creating a data file. Users create data files. 1. File naming conventions refer to the guidelines followed while assigning file names and will vary with the operating system and application in use (see figure 4-1). File names in Windows 7 may be up to 255 characters, you're not allowed to use reserved characters or certain reserved words. File extensions are used to identify the application that was used to create the file and format data in a manner recognized by the source application used to create it. FALL 2012 1 II. Selecting secondary storage media A. There are three type of technologies for storage devices: magnetic, optical, & solid state, there are advantages & disadvantages between them. When selecting a secondary storage device, certain factors should be considered: 1. Capacity - the capacity of computer storage is expressed in bytes.
    [Show full text]